Cant go wrong with a 14.5 pin and welded upper - Aero Precision M4E1 14.5in 5.56 NATO Threaded Complete Upper Receiver

My second 14.5 aero upper, can’t go wrong. Aero thought ahead by using a slim muzzle break so you can swap out different gas blocks and hand gaurds. If you don’t want a tax stamp, 14.5 is the way to go. With pin and welded upper you get a shorter profile while maintaining compliance. I put around 500 rounds through this upper and so far it’s holding up well. No issues. I would hold off til you get this upper on sale since aero does have manufacture sales or optic planets many coupon discounts.